The first big test for American presidential candidates unfolded across Iowa on Monday night as more than 100,000 people across the Hawkeye State were expected to travel to more than 1,600 precincts to discuss who they want to elect as the next commander-in-chief of the United States. The process starts at 8 p.m. EST.

The results will roll in  throughout the night. If you're interested in following along, you can tune into live broadcasts from C-SPAN here or ABC News here. Both videos are embedded below.

The Des Moines Register will also feature live video on its website here, though the feed won't launch until the caucuses actually begin.

Heading into Monday night, real estate mogul Donald Trump was leading the crowded field of Republican candidates, with about 31 percent of the Iowa caucus vote. Texas Sen. Ted Cruz was trailing him with about 24 percent and Florida Sen. Marco Rubio was in third place with about 17 percent. They were the only three GOP candidates whose support was in the double digits, according to the HuffPost Pollster's Iowa caucus poll aggregator.

The race was similarly tight on the Democratic side: Former Secretary of State Hillary Clinton had about 48 percent of the vote and Vermont Sen. Bernie Sanders had about 45 percent. Former Maryland Gov. Martin O'Malley was polling at the bottom of the shorter list of candidates with about 4 percent.

GettyImages-506958072 Iowans await the arrival of Republican presidential candidates in Marshalltown, Iowa, Jan. 26, 2016. Photo: Getty Images

CNN reported that viewers should carefully watch how many people turn out as the night wears on, as the Iowa caucus process requires people to physically meet up in locations like schools, libraries and churches. There, the campaigns can make final pitches to garner Iowans' support. The process is different for each political party. The GOP collects paper ballots, but the Democrats make people stand in groups for their top candidate.

Sanders has campaigned heavily on Iowa college campuses in hopes of motivating new voters to caucus in his favor. "It comes down to who can grind it out on the ground on Monday night,” political pundit David Axelrod, who led President Barack Obama's campaigns, told the Register. "If turnout is within a normal range, Hillary likely wins. If it goes higher, approaching 200,000, it will be a good night for Bernie."

High turnout could also benefit Trump — and his rivals know it. “This race is a statistical tie between me and Donald Trump,” Cruz said at a last-minute event Monday, the Washington Post reported. “It all comes down to turnout, who shows up at 7 p.m.”